1. Field of the Invention
The present invention relates to a lithium rechargeable battery, and more particularly to a lithium rechargeable battery adapted to prevent a formation process contact pin from slipping on the head of the battery's electrode pin.
2. Discussion of the Background
Portable electronic appliances may require batteries having a high energy density, such as rechargeable lithium batteries, as their power source.
Lithium rechargeable batteries create electric energy by oxidation and reduction reactions during intercalation and deintercalation of lithium ions at the positive and negative electrodes. Materials that enable lithium ions to undergo reversible intercalation and deintercalation are used as the active materials of the positive and negative electrodes of lithium rechargeable batteries. In addition, an organic electrolyte or a polymer electrolyte may be used to fill the space between the positive and negative electrodes.
Lithium-containing metal oxides such as lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), and lithium manganese oxide (LiMnO2) may be used as the positive electrode active material of the lithium rechargeable batteries. Lithium metal or lithium alloy may be used as the negative electrode active material.
However, lithium batteries may short-circuit and explode when lithium metal is used due to dendrite formation. Therefore, lithium metal may be replaced by carbon-based materials, such as amorphous carbon and crystalline carbon. The lithium rechargeable batteries may be manufactured in various shapes, such as cylinders, squares, and pouches.
FIG. 1 is an exploded perspective view showing a conventional lithium rechargeable battery.
Referring to FIG. 1, the lithium rechargeable battery may be formed by placing an electrode assembly 12 including a first electrode 13, a second electrode 15, a separator 14, and an electrolyte into a can 10 and sealing the top of the can 10 with a cap assembly 20.
The cap assembly 20 may include a cap plate 40, an insulation plate 50, a terminal plate 60, and an electrode pin 30. The cap assembly 20 may be coupled to the top opening of the can to seal the can 10 and may be insulated from the electrode assembly 12 by a separated insulation case 70.
The cap plate 40 may be made of a metal plate with a size and a shape corresponding to the top opening of the can 10. The cap plate 40 may have a terminal through-hole 41 arranged at its center. The electrode pin 30 may be inserted into the terminal through-hole 41. A tubular gasket 35 may be coupled to the outer surface of the electrode pin 30 to insulate the electrode pin 30 from the cap plate 40 when the electrode pin 30 is inserted into the terminal through-hole 41. The cap plate 40 may have an electrolyte injection hole 42 arranged on one side and a safety vent (not shown) arranged on another side. The safety vent may be integrally formed by reducing the sectional thickness of the cap plate 40. The cap assembly 20 may be assembled to the top opening of the can 10, and an electrolyte may be injected via the electrolyte injection hole 42, which is then sealed by a plug 43.
The electrode pin 30 may be coupled with a second electrode tab 17 of the second electrode 15 or to a first electrode tab 16 of the first electrode 13. The electrode pin may act as a second or first electrode terminal. The first electrode tab 16 and the second electrode tab 17 may be drawn out of the electrode assembly 12. Insulation tape 18 may be wound around portions of the first electrode tab 16 and the second electrode tab 17 to prevent a short circuit between the first electrode 13 and the second electrode 15. The first electrode 13 or the second electrode 15 may act as a positive or negative electrode.
After assembly, the lithium rechargeable battery may undergo a series of formation processes including charging, aging, and discharging to stabilize the battery structure and make it ready for use. The formation process equipment may include a contact pin, which may be used to charge the battery to give it desired characteristics or to inspect the battery's performance. The contact pin may slip in the lateral direction on the head of a conventional electrode pin and cause poor contact. This may degrade the battery's performance, life span, and safety.